scholarly journals Effect of material heat treatment on fatigue crack initiation in austenitic stainless steels in LWR environments.

2005 ◽  
Author(s):  
O. K. Chopra ◽  
B. Alexandreanu ◽  
W. J. Shack
Keyword(s):  
Heat Treatment ◽  
Fatigue Crack ◽  
Crack Initiation ◽  
Stainless Steels ◽  
Fatigue Crack Initiation ◽  
Austenitic Stainless Steels

scholarly journals Mechanism of Fatigue Crack Initiation in Austenitic Stainless Steels in LWR Environments

2002 ◽  
Author(s):  
Omesh K. Chopra
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Stainless Steels ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Austenitic Stainless Steels ◽  
Fracture Morphology ◽  
Fatigue Tests ◽  
Temperature Level ◽  
Metallographic Examination

This paper examines the mechanism of fatigue crack initiation in austenitic stainless steels (SSs) in light water reactor (LWR) coolant environments. The effects of key material and loading variables, such as strain amplitude, strain rate, temperature, level of dissolved oxygen in water, and material heat treatment on the fatigue lives of wrought and cast austenitic SSs in air and LWR environments have been evaluated. The influence of reactor coolant environments on the formation and growth of fatigue cracks in polished smooth SS specimens is discussed. Crack length as a function of fatigue cycles was determined in air and LWR environments. The results indicate that decreased fatigue lives of these steels are caused primarily by the effects of the environment on the growth of cracks <200 μm and, to a lesser extent, on enhanced growth rates of longer cracks. A detailed metallographic examination of fatigue test specimens was performed to characterize the fracture morphology. Exploratory fatigue tests were conducted to enhance our understanding of the effects of surface micropits or minor differences in the surface oxide on fatigue crack initiation.

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